1. Field of Invention
The present invention relates to a refrigerator, and more particularly, to a cold air supply device for a refrigerator capable of supplying cold air directly to stored goods when the stored goods are put on a shelf in a storage space of the refrigerator.
2. Description of the Prior Art
A refrigerator includes a storage space for keeping food to be stored in a refrigerated or frozen state. The storage space is supplied with cold air that is generated through contact of air with a heat exchanger of a freezing cycle.
FIG. 1 is a longitudinal sectional view showing the interior of a general refrigerator. As shown in the figure, a refrigerator main body 2 comprises an outer case 4a of a steel plate and an inner case 4b installed inside the outer case 4a. In addition, an insulating material 6 is provided between the outer case 4a and the inner case 4b. 
Further, the interior of the refrigerator main body 2 is formed to be divided into a refrigerating chamber 8a and a freezing chamber 8b that are storage spaces. Refrigerating and freezing chamber doors 10a and 10b are installed at front faces of the refrigerating and freezing chambers 8a and 8b, respectively. The doors 10a and 10b, which are installed pivotably about their respective sides that are supported by the refrigerator main body 2, selectively open and close the refrigerating and freezing chambers 8a and 8b, respectively.
The refrigerating and freezing chambers 8a and 8b are partitioned with a barrier 12. An insulation layer is also provided in the barrier 12. In the illustrated example of the prior art, a cold air connecting passage 14 is formed in the barrier 12. The cold air connecting passage 14 allows the cold air to be supplied into the refrigerating chamber 8a. 
A heat exchange chamber 16 is provided at a rear portion of the freezing chamber 8b and an evaporator 18 is installed in the heat exchange chamber 16. A refrigerant channel (not shown) is formed in the evaporator 18. While a liquid refrigerant at low temperature and pressure is introduced into and flows in the refrigerant channel, the refrigerant is evaporated through heat exchange with the surrounding air, and the evaporated refrigerant flows to a compressor (not shown). Since the liquid refrigerant absorbs surrounding heat while flowing within the evaporator 18, the air in contact with a surface of the evaporator 18 is changed into cold air. The cold air thus generated is supplied to the aforementioned refrigerating and freezing chambers 8a and 8b, so that it is possible to keep the stored food in a refrigerated and frozen state.
For example, the cold air generated in the heat exchange chamber 16 is supplied to the refrigerating and freezing chambers 8a and 8b by a blowing fan 17. The freezing chamber 8b is directly supplied with the cold air by the blowing fan, while the refrigerating chamber 8a is directly supplied with the cold air through the cold air connecting passage 14 formed in the barrier 12 between the heat exchange chamber 16 and the refrigerating chamber 8a. In addition, for example, side ducts 20 are installed on both side surfaces of the refrigerating chamber 8a. 
Thus, the cold air subjected to the heat exchange in the heat exchange chamber 16 is supplied to the side ducts 20 through the cold air connecting passage 14 in the barrier 12, and the cold air supplied to the side ducts 20 is then supplied to the refrigerating chamber 8a through cold air discharge ports 22 formed in the side ducts 20. When the cold air is supplied to the refrigerating chamber 8a, the refrigerating chamber 8a is maintained in a low temperature state, and thus, goods and the like to be stored can be kept in the refrigerating chamber 8a. 
However, the conventional refrigerator has the following problems.
That is, in the prior art, when the interior of the storage space is supplied with the cold air, it is impossible to control the amount of cold air to be discharged through the air discharge ports 22. In other words, the cold air is merely supplied into the storage space through the cold air discharge ports 22 after checking temperature in the storage space. That is, the cold air is supplied into the storage space through the cold air discharge ports 22 regardless of the presence of stored goods near the cold air discharge ports 22. In such a case, there is a problem in that it is impossible to keep the stored goods fresh since the cold air cannot be supplied intensively to a portion, which requires the cold air, in an efficient manner.